If it is a circular mirror the line would be called a radius. If it is a rectangular or square mirror it would just be called a diagonal or straight line... nothing special
optical axis
It's an Optical Axis.
Optical axis. There ya go!
a straight line
Is it A)focal point B)optical axis C)angle of incidence D)fulcrum
The straight-line distance is 1,030 miles (to the coastline of Puerto Rico). This is the true straight line distance which accounts for the curvature of the earth, NOT simply a straight line drawn on a map.
A chord is a straight line drawn through a circle which divides the circle into two parts. The line can be drawn anywhere in the circle EXCEPT the center where it becomes the diameter.
vertical
Horizontal
beam
Rake can be described as an angle at which the headstock of the motorcycle is inclined when compared against a vertical line drawn perpendicular to the ground. Trail is the distance on the ground between a straight line drawn through the center of the front wheel spindle and a line drawn through the center of the headstock axis. Taken from http://bikearama.com/theory/motorcycle-rake-trail-explained/
The straight-line distance is 1885.7 miles. This is the true straight line distance which accounts for the curvature of the earth, NOT the straight line drawn on a map.